Hydrodynamical analysis of centrality dependence of charged particle's multiplicity in $\sqrt{s}_{NN}$=2.76 TeV Pb+Pb collisions

TL;DR

This paper uses Israel-Stewart hydrodynamics to analyze ALICE data from Pb+Pb collisions at 2.76 TeV, determining the thermalization time that best fits the centrality-dependent charged particle multiplicity and elliptic flow.

Contribution

It provides a hydrodynamical analysis that constrains the thermalization time in high-energy heavy-ion collisions using recent experimental data.

Findings

Optimal thermalization time around 0.88 fm

Very early or late thermalization times are disfavored

Data successfully explained by the hydrodynamical model

Abstract

In Israel-Stewart's theory of dissipative hydrodynamics, we have analyzed the recent ALICE data for the centrality dependence of charged particle multiplicity, centrality dependence of integrated elliptic flow and 0-5% charged particles $p_T$ spectra in $\sqrt{s}_{NN}$=2.76 TeV Pb+Pb collisions and determined the initial or the thermalisation time. Analysis indicate that the ALICE data disfavor very early thermalsiation $\tau_i$=0.2 fm, or very late thermalsation $\tau_i$= 4fm. Data are best explained for thermalisation time $\tau_i=0.88^{-0.14}_{+0.68}$ fm.